EquineMATTERS

SPRING EDITION 2011

www.xlvets.co.uk

Inside this issue:

INFERTILITYAND ABORTION IN MARESThis article aims to answer some of themany questions posed about infertility andthe problems of abortion in mares.

SPLINT BONEFRACTURESWe focus on fractures of the splint bones;a relatively common injury in horses.

FOR OUR YOUNGER READERS

Contact your XLVets practice for more details

Spot theDifference!Worms could severely affect the health of one ofthese horses, you can make that difference...

...Improve your horse’s health whilst reducing costs with the XLVets innovative approach to worm control.

XLVets Member Practices608 Vet GroupAllen and PartnersAlnorthumbria Veterinary GroupArdene House Veterinary HospitalArmour Veterinary CentreBelmont Veterinary CentreBishopton Veterinary GroupCain Vet CentreCalweton Veterinary PracticeCapontree Veterinary CentreCastle Veterinary SurgeonsChapelfield Veterinary PartnershipCliffe Veterinary GroupClyde Veterinary GroupDrove Veterinary HospitalEndell Veterinary GroupFarm First Veterinary ServicesFenwold Veterinary CentreFriars Moor Veterinary ClinicGlenthorne Veterinary GroupHook Norton Veterinary SurgeonsKingfisher Veterinary PracticeKingsway Veterinary GroupLambert, Leonard & MayLarkmead Veterinary GroupMacpherson O’Sullivan LtdMillcroft Veterinary GroupMinster Veterinary PracticeNorthvet Veterinary GroupParagon Veterinary GroupParklands Veterinary GroupPAWS Veterinary Health CentrePenbode Veterinary GroupRosevean Veterinary PracticeRutland Veterinary CentreScarsdale Veterinary HospitalScott Mitchell AssociatesShepton Veterinary GroupSouthfield Veterinary CentreSt Boniface Veterinary ClinicSynergy Farm HealthThrums Veterinary GroupTyndale Farm Veterinary PracticeWensum Valley Veterinary SurgeonsWestmorland Veterinary GroupWillows Veterinary GroupWright & Morten

XLVets is a novel and exciting initiative conceived from within the veterinary profession.We are all independently owned, progressiveveterinary practices located throughout theUnited Kingdom committed to working togetherfor the benefit of our clients.

SPRING EDITION

C O N T E N T S

T H E E D I TO R

Welcome to the ‘First’ issue of Equine Matters...Welcome to XLVets equine newly revampednewsletter for 2011- Equine Matters. Themagazine will continue to evolve over thisyear and Liz Jackson will be taking over as the new editor. If you have any ideas or wish to submit pictures please forward them to the XLVets office. We hope that you are all enjoying riding again after theenforced rest for many horses with the

snow at the end of 2010 and everyone is looking forward to the new season. Asalways if anyone has any queries arisingfrom these articles please contact your local XLVets practice where your vet can discuss them further.

Equine Matters is published by:XLVet UK Ltd, Carlisle HouseTownhead Road, DalstonCarlisle CA5 7JFTel: (01228) 711788*This publication is supplied free of charge toequine clients of XLVets member practices.

© XLVet UK LtdNo part of this publication may be reproducedwithout prior permission of the publisher.Disclaimer:XLVets does not necessarily share the views of contributors. No responsibility can be acceptedfor opinions expressed by contributors, or claimsmade by advertisers within this publication.

CONTENTSEQUINE HEALTH

09 Equine Influenza:A review of the characteristics ofEquine Influenza (Flu) and the benefitsof vaccination.

13 Allergic skin disease in horses:Richard Morris of Fenwold VeterinaryCentre looks at a number of agentsthat cause allergic skin reactions in the horse.

REPORTS03 Infertility and abortion in mares:

A report by Louise Cornish of ClydeVeterinary Group.

07 Splint bone fractures:A report by Ben Sturgeon of CastleVeterinary Surgeons.

11 An old codger’s blog:The concluding part of an insider’sview of the life and management ofthe mature horse.

15 Airway anatomyMark Tabachnick of Wright & Mortengives a detailed account of the anatomyof the equine respiratory system.

SPRING FEATURE

We review three main areas where those of uswho keep and care for the horse need to alterour approach to worm control.

05A modern approach toworming horses...

Wendy Furness MA VetMB CertEP MRCVSScarsdale Veterinary Hospital

!

R E P R O D U C T I O N

Why is it that some mares appear to fall pregnant very easily andothers don’t? How is it possible that your mare is pregnant at her

21 day scan but not a week later? What causes a mare to abort at 8months despite being apparently healthy on the outside? This article aimsto give a few answers to these questions, although, unfortunately, thereproductive science of horses is not an exact one.

Veterinary Surgeon Louise Cornish

Binscarth Farms

IN MARESINFERTILITYMares fail to become pregnant for many reasons, some of the most common being:

l Poor timing of breeding - either too earlyor too late.

l Poor quality of semen - especially ifchilled or frozen for artificial insemination.

l Age of the mare - older eggs are of poorer quality, and the uterine lining canbecome scarred with age, even in a maiden mare.

l Malnutrition or obesity - mares should belean and receiving good quality feeding.

l Endometritis - inflammation within the lining of the womb, which may be eitherpresent long-term due to infection orbrought on by semen irritating theendometrium after breeding.

l Infectious disease, such as ContagiousEquine Metritis (CEM) or Equine ViralArteritis (EVA).

It is important to remember the pregnancyrates which exist, even when conditions forbreeding are ideal. Approximately 60% ofyoung, healthy mares which are provided

with fresh good quality semen conceive ontheir first service or covering. So, say you startwith 100 mares, 40 are left empty. At thenext attempt, 60% of these 40 are likely toconceive, leaving 16 not in foal. If a thirdattempt is made, statistically 6 mares are likely not to be pregnant. By this time, thereshould be strong suspicions that something isgoing wrong with the stallion, mare or covering/insemination regime, but you maysimply be unlucky enough to have one of the 6 mares in our scenario which have happened not to conceive!

XLVets Practice Clyde Veterinary Group, Lanarkshire

INFERTILITY & ABORTION

Louise Cornish BVMS, CertEP, MRCVS Clyde Veterinary Group

3 EQUINE MATTERS

POSSIBLE VETERINARYINVESTIGATIONS:

l Vaginal examination

l Clitoral or uterine swabbing

l Ultrasonographic examination

l Endoscopic examination

l Uterine biopsy

l Blood samplingUltrasound of a 15 day pregnancy

WHAT CAN I DO TOREDUCE THE LIKELIHOODOF MY MARE ABORTING?

R E P R O D U C T I O N

SPRING 2011 ISSUE EQUINE MATTERS 4

EMBRYONIC OR FOETAL LOSSUnfortunately, loss of a developing foal is notuncommon, especially at the early stages ofpregnancy. If the embryo dies before 80days of age, it will probably be resorbed by the uterus (womb) of the mare, and no outward signs of abortion will be present.After 80 days, the foetus and placenta willusually be expelled via the vagina. Theremay or may not be any traces of the abortionhaving taken place, depending on theamount of blood or discharge present andthe management of the mare. It is, therefore,relatively common for a vet to be called to examine a mare which is overdue for foaling, only to discover that she is no longer pregnant despite a positive scan theprevious spring.

An aborting foal can be dangerous for amare, especially in the last few months ofpregnancy, as the foal may not present in thenormal position. It is also very common forthe placenta not to be passed as normal,resulting in Retained Foetal Membranes(RFM), which can quickly lead to toxaemiaand laminitis.

Causes of embryonic or foetal loss include:

l Abnormal genetics - the womb of a maremay ‘recognise’ abnormal chromosomesin a young embryo and terminate thepregnancy.

l A poor uterine environment - multiplelarge endometrial cysts, uterine infection or scarring prevent a 17 day old embryofrom successfully implanting into the wallof the womb.

l Fixation in the wrong part of the uterus - such as in the horn tips or in the uterine body.

l Severe stress, trauma or malnutrition -fairly uncommon causes in reality -although often blamed.

l Pyrexia (fever) in the mare due to an unrelated infection - such as influenza or strangles.

l Insufficient amounts of progesterone -there is little evidence to suggest that poorproduction of this hormone by the ovariesis a common cause of miscarriage, butoral supplementation with a syntheticequivalent is sometimes recommended,especially if a blood sample has shownlow progesterone levels.

l Placentitis - bacterial infection of the placenta usually develops due to infectioncreeping up through the cervix from thevagina, especially in the later stages of pregnancy.

l Twins - a mare’s uterus has evolved tocarry only one foal to term, and less than5% of twin pregnancies will result in twolive foals. Of the other 95%, many willsafely lose one embryo very early on inthe pregnancy, but about a third of mareswill abort both foals in the last trimester. This is distressing for all concerned, aswell as being dangerous for the mare, as difficult births and RFM are common.

l Equine Herpes Virus (EHV-1) - this viruscauses respiratory disease and is oftenreferred to as ‘the cold’ in equine circles,but also causes abortion in the secondhalf of pregnancy in mares.

l Equine Viral Arteritis (EVA) - this virus is not normally present in the UK but isoccasionally found in imported mares orstallions and is notifiable. A vaccine isavailable for use in stallions but must beobtained under licence.

l Arrange a pre-breeding check fromyour vet to pick up abnormalities thatcan be addressed before conception

l Two ultrasonographic scans before 35 days gestation to detect twins

l Provide good quality nutrition butavoid too much weight gain

l Encourage regular but not excessiveexercise

l Ensure she has a relatively stress-freeand hygienic environment

l Keep brood mares separate from horses that are regularly travelling tocompetitions/riding club

l Vaccinate for EHV-1 at 5, 7 & 9months of pregnancy

If you do suspect that your mare has losta foal, it is highly recommended thatyour vet examines the mare for her ownsafety. If you do find the foal and/orafterbirth, keep them so that your vet can examine them too - it may be possible to make a diagnosis as to thecause of the abortion, or they may besent to a laboratory for further tests. Thisis especially important if there are otherpregnant mares on the premises.

Depending on the cause of the loss, your vet may be able to advise you as to whether it would be wise to attempt to breed the mare again onanother occasion.

IF YOU SUSPECT THATYOUR MARE HAS LOSTA FOAL...

Ultrasound of a 40 day pregnancy

W O R M I N G

Veterinary Surgeon Julian Rishworth

XLVets Practice Minster EquineVeterinaryClinic, York

5 EQUINE MATTERS

Everyone in the horse industry has becometoo over-reliant on the use of anthelmintics(wormers) as the treatment of choice for controlling worms in our horse population. The drugs we have had available have beena pretty efficient way of removing worms fromthe horse, however, when you keep attackinga worm population with highly effective products over a long period of time you pressurise that worm population to produceresistance to those products.

We are now at that stage where resistance tothe worming medications we have available

is becoming more and more common. It is notthe worming products that are getting weaker;it is the worm population that is becomingstronger. The other problem we have is thatthere are not lots of new chemicals beingdeveloped that can help deal with these resistant members of the worm population.

It is not total doom and gloom and there arestill things we can all do to improve the waywe manage the worm burdens in our horsesand at the same time ensure that we canextend the effective useful period of the drugswe currently have available.

A modern approach to

worming horsesLike the action required to arrest the problems with global warming, we all have a fair idea that it is important, we all would like to do our bit to help but actuallydoing everything we should do is more difficult to achieve in real life. Worming horses has become such an integral part of the keeping of horses that horse ownershave become very entrenched in their own traditional methods of worm control.

Julian Rishworth BVetMed, MRCVS

W O R M I N G

SPRING 2011 ISSUE EQUINE MATTERS 6

The XLVets Equine Forum has done a lot ofwork to develop a modern approach to wormcontrol in the horse, in conjunction withProfessor Chris Proudman, a recognised worldauthority on the subject. There are three mainareas where those of us who keep and carefor the horse need to alter our approach toworm control; l Effective pasture managementl Identifying those horses with significant

worm burdensl Appreciating what is an acceptable level

of worm burden in the horse

Effective Pasture Management Pasture management alone can be a highlyeffective method of worm control for thehorse. The life-cycle of worms requires eggspassed in the faeces to contaminate the

pasture, whereby the larvae from the hatchedworm eggs can go on to re-infect that, orother horses. Efficient removal of the faecesfrom the pasture is a great method of breaking that life-cycle. Many owners doclear droppings from the pasture and traditional advice has been that this should be done twice a week. Many owners who,for whatever reason, cannot achieve this rateof pasture clearance may not be motivated to use this highly effective method of control.Recent research has shown that clearing thedroppings even on a less frequent basis, upto once per fortnight can still be highly effective at controlling horse worm burdens. If the stocking density is high then more frequent clearance of droppings may be necessary, but, for average stocking densities(1-2 horses per acre) once a fortnight clearance of droppings is highly effective and a much more achievable target for most horse owners.

Faecal Worm Egg Counts (WEC)Measuring the concentration of worm eggs inthe horse’s faeces can not only tell us a howsevere an infestation of worms that particularhorse has, but it can also be used to measurehow effective the anthelmintic (wormers) drugsare being. In any group of horses there are usually onlya few (10-20% or 1 or 2 out of every 10)that are significantly contaminating the pasturewith a high concentration of worm eggs intheir faeces. Performing WEC’s allows us toidentify which of the group of horses havethese high concentrations of worm eggs intheir faeces, so we can target our treatmentsat these horses. A lot of owners believe that they need to try to keep their horses‘worm-free’ and the aim of their worm management programme is to try to achievethis. One of the new ideas we need to

embrace is the concept of horses having anacceptable level of worm burden. In the sameway that we recognise that trying to rid thehuman body of all bacteria is not only impossible but also really bad for our healthand well-being. We need to realise that thepresence of a few worms in our horses mayactually be good for them. There is research to suggest that acceptable levels of worms inhorses may help prevent nasty conditions suchas Grass Sickness and research from humanmedicine points to low levels of worm burdensbeing protective against allergic respiratoryconditions such as asthma. As more and morework is done in this area, there is likely to bemore valuable information like this. Worm egg count (WEC) results in the regionof 200-400 eggs per gram of faeces shouldbe considered as acceptable and only horsesreturning results higher than this will requiretreatment with a wormer. Another use of the WEC tests is to measure theeffectiveness of the wormers we use to treat thehorses. If a faecal sample is tested 2 - 4 weeksafter a treatment with a wormer and the result is not zero, then there is a strong suspicion that there is a resistance problem in the worm population, on that premises, to the wormerused. This is valuable information which vetscan use to help formulate and adapt the wormcontrol programme on that premises. UsingWEC’s as part of the standard worm controlprogramme for our horses is something we areall going to have to get used to and the abilityto identify those horses that actually need treatment and only treat those horses is not only a more efficient use of the worming drugs,it also makes financial sense, too. Nobodywould think it sensible to treat our horses with antibiotics every 6 weeks just in case theremight be an infection, so we need to appreciate the way we have been used to using anthelmintics (wormers) is similarly inappropriate.The XLVets Equine Forum has produced abooklet entitled ‘Effective Worm Control inHorses’ which is available from your localXLVets practice. The booklet explains in detail,the modern approach to worm control andshows plans for different age groups of horses. If you need further advice your vet willbe happy to discuss a programme with you.

J U L I A N R I S H WO RT H

...One of the new ideas we need to embrace is the concept of horses having an acceptable level of worm burden. We need to realise that the presence of a fewworms in our horses may actually be a good thing.

S P L I N T B O N E S

Veterinary Surgeon Ben Sturgeon

XLVets Practice Castle Veterinary Surgeons, Durham

7 EQUINE MATTERS

Metacarpal and metatarsal bones II and IV (splint bones) are rudimentary ancestral structures found pairing each cannon bone. Anatomically the bones support the lower rows of hock and knee bones

and are attached to the cannon by a thin interosseous ligament. Fractures of the splint bones are a relativelycommon injury. They may result from direct external trauma (usually kicks) but may also be secondary toabnormal internal forces, most commonly associated with suspensory ligament desmitis (swelling of the ligament), particularly in horses that race over fences.

Splint Bone FracturesBen Sturgeon BVM&S, BSc, CertEP, MRCVS Castle Veterinary Surgeons

The fractures can theoretically occur on any of the splints, although those associated withinternal forces are more commonly found in the forelimbs, with the left fore being more frequent on the outside splint and the right foreon the inside splint. This may be associatedwith counter-clockwise work (most research hasbeen carried out in racing Thoroughbreds)resulting in increased loading on these areas.Here the distal ends of the splints attach to theproximal sesamoid bones by fibrous bandswhich may stretch during fetlock hyper oroverextension commonly when the leg is fullyweight bearing and the fetlock is at its lowestpoint of the stride. This resulting ‘tug of war’stresses the attachments predisposing to fracturegenerally in the lower third of the bone. Suspensory desmitis may also precede or gohand in hand because of similar stresses beingplaced on the structure, the resultant swellingcreating a ‘bowstring’ effect from the enlargedsuspensory leading to a progressive deviationof the splint away from the cannon. Poor knee and/or foot conformation will furtherexacerbate or predispose to the condition.

Kicks are the more common presentation withwounds often being open and discharging with heat and swelling and the horse will be obviously and acutely lame. Occasionally,a chronic low grade lameness or dischargingtract are found weeks after a trauma whichprompts investigation and the finding of a fracture.

Irrespective of the aetiology, wound assessmentand classification of the fracture itself, alongwith any potentially involved surrounding structures are vital before any treatment is discussed and implemented. This is primarilyachieved by radiographic evaluation combinedwith ultrasound of the ligamentous attachments.X-rays will invariably reveal the fracture often inpieces (comminution) although the basic axialalignment of the bone and fragments is still usually present, the presence of infection, displacement of the fractured portion andinvolvement of the cannon can also be discerned. Furthermore, x-rays may reveal pre-existing abnormalities of the splints (callusformation) suggestive of long-term suspensoryligament problems.

Irrespective, the first and most important consideration to be made (from the

radiographs) is whether the affected splint is stable or not. Fractures of the upper portion,invariably due to kicks, may result in instabilityof the carpus or hock (particularly of the innersplints of the forelimbs), long term resulting ininterosseous ligament damage, osteoarthritisof the joints or even avulsion (dislocation) ofthe upper portion of the splint. In such casessurgical fixation would be necessary to fix the splint to the cannon bone using a combination of screws and steel plate (figures1 and 2.) Where infection is present or suspected, fixation techniques may be withheld until the infection is cultured andresolved by use of appropriate antibiosis.

Figure 1: Fractured head of splint

Figure 2: Post-operative radiograph following stabilisation

S P L I N T B O N E S

SPRING 2011 ISSUE EQUINE MATTERS 8

If the fracture does not affect stability, isnon-infected, and is simple (the bone fragments are relatively unified) then treatment is generally conservative withheavy supportive bandaging and a periodof enforced rest (12-14) weeks with regularradiographic re-evaluations to assess thequality of healing before embarking on acontrolled exercise programme followingconformation of satisfactory healing figures 3, 4 and 5.)

Treatment of a non-infectedsplint bone fracture

Figure 3: Mid body fracture following kick

Figure 4: Healing at 6 weeks

Figure 5: Healing at 12 weeks

Occasionally, despite appropriate rest and support the healed fracture callus may still result in a callus which irritates the suspensoryligament causing a mild lameness. Surgicaldebridement of the callus may be necessary,although injection of local anti-inflammatoriesmay suffice.

Where the fracture is thought to be secondaryto internal forces, treatment may be either conservative or surgical, with many advocatingrest to allow the often concomitant ligamentousdamage to resolve; if however the fracturedfragment is avulsed or demonstrating poor quality healing then surgical ostectomy is againadvocated with removal of the bottom piece ofbone, along with torn ligaments and roundingof the remaining portion. Occasionally, involvement of the splint, suspensory ligamentand the proximal sesamoid bones is seen (often called the three S’s) and all three need tobe evaluated before the appropriate treatmentand prognosis is decided upon and given.

Periodically, trauma may result in infectionand/or discharge either through introduction of bacteria or through sequestration (bone fragment death). In such cases antibiotics and flushing are advisable although surgicaldebridement of the wound or removal of thedistal fragment and bony pieces may be necessary irrespective of the site of the fracture(figure 6 and 7).

Figure 6: Unstable mid body fracture

Figure 7: Intra-operative radiograph following resection

THE PROGNOSIS

In the vast majority of cases the prognosis for return to previous work is good, irrespective of whether the treatment employed has been surgical or conservative. The overriding factor affecting prognosis is whether or not the suspensory ligament is damaged highlighting that ultrasonographic evaluation of the suspensory early on in diagnosis and treatment is advisable as well as regular lameness evaluations during the recovery course (3 - 6 months). This may elicit an earlier surgical interference, indicate the need for adjunctive therapies such as extracorporeal shock wave therapy or steroid injections, or simply alter a prognosis and the client/patient expectations.

E Q U I N E I N F L U E N Z A

9 EQUINE MATTERS

Equine Influenza (Flu)A viral disease of horses worldwide...

Equine Influenza (Flu) is an important viral disease of horses worldwide. The disease is caused by EquineInfluenza Virus, which is related to the virus which causes outbreaks of human flu every year. The virus

mainly affects the respiratory system and can cause fever, lethargy, poor appetite, nasal discharge and a harsh dry cough. The majority of affected horses recover within a few weeks. However, secondary complications due to bacterial infection can lead to pneumonia and very severe, even fatal, disease insome horses. In such cases, full recovery can take several months. The disease is highly contagious and can spread rapidly from horse to horse.

E Q U I N E I N F L U E N Z A

SPRING 2011 ISSUE EQUINE MATTERS 10

Equine Flu in the UKFlu is found worldwide, with the exception of a few countries such as Australia and Iceland.Regular outbreaks are reported in the UK, with 10 reports in 2010 (see Table 1). For thisreason, it is vital to ensure that all horses areprotected against this important disease.Vaccination is the best way of protecting yourhorse against flu, and is mandatory for anyhorse competing under Jockey Club or FEI rules.

Flu is evolving...One of the characteristics of the viruses whichcause human and equine flu is that they tend tomutate and change over time. This can causeproblems with vaccination, as the strains of fluin the vaccines can go ‘out of date’, whichmay result in less effective protection againstdisease. This is the reason why human flu vaccines are updated every year. It is also recommended that equine flu vaccines areupdated regularly, to ensure the closest possible match between the vaccine and thestrains of flu virus circulating in the environment.

‘Why should I vaccinate?’ I hear you cry!Firstly your horse will feel exactly the same aswe do when we have the flu - rotten. Also,in becoming infected your horse stands areal chance of infecting many others with thevirus. Finally, as you are all probably aware,to compete with your horse you will need anup to date passport demonstrating yourhorse's up to date vaccination status.

On May 11th 2010

Equine flu was diagnosed in LINCOLNSHIRE

On May 21st 2010

Equine flu was diagnosed in SHROPSHIRE

On June 8th 2010

Equine flu was diagnosed in SURREY

On July 15th 2010

Equine flu was diagnosed in NOTTINGHAMSHIRE

On August 13th 2010

Equine flu was diagnosed in NOTTINGHAMSHIRE

On August 16th 2010

Equine flu was diagnosed in WORCESTERSHIRE

On August 25th 2010

Equine flu was diagnosed in SOUTH LANARKSHIRE

On September 2nd 2010

Equine flu was diagnosed in HAMPSHIRE

On September 3rd 2010

Equine flu was diagnosed in CUMBRIA

On November 3rd 2010

Equine flu was diagnosed in LEICESTERSHIRE

Benefits of vaccinationThe benefits of vaccination were demonstratedvery publicly during the 2007 AustralianEquine Influenza outbreak. The horse population in Australia had never beenexposed to equine flu before and as such, no horses had been vaccinated. Some infected horses entered an Australian

quarantine station near Sydney and the virusescaped. The infection spread rapidly andover 76,000 horses became infected, located on more than 10,000 premisesthroughout Queensland and New SouthWales. Vaccination, along with the restrictionof horse movement, stopped this infection in its tracks and prevented the flu virus fromspreading all over Australia.

Nasal discharge, typical sign of a horse with Equine Influenza.

Table 1: Equine Flu outbreaks in the UK in 2010FACT...

The number of horses vaccinated in the UK is less than 40% and isdeclining. If this continues we willrisk more frequent and larger outbreaks. Please talk to your vet about equine flu vaccination foryour horse.

T H E M AT U R E H O R S E

11 EQUINE MATTERS

PART 2OF A TWO PART SERIES

An old codger’s blogAn insider’s view on the life and management of the mature horse... As told to Dr Teresa Hollands R.Nutr

Something owners need to remember is wedo like to be kept occupied. I’ve more timeon my hands now and standing around in abare paddock, (beats being stuck in a stable,better for my joints and my brain) withoutsome hay is deadly.

I know that there are rumours about hay shortages this year, but we’ve lived throughseveral of these shortages (1977, 1994,2006) and it’s never as bad as the headlinessuggest. BUT, I have a psychological need tochew and if she restricts the grass too muchand doesn’t give me hay, then I’ll eat herfence posts and the bark of the trees. OK I understand why she restricts my grass as Ido have a tendency to gain weight now I am no longer hacking to shows.

But the latest research has shown that if yourestrict fibre then you increase the risk of l wood chewing, (Walters)l gastric ulcers, (Murray)l colic, (Hillyer)

So what she needs to do is soak my hay for12hrs and then let me have enough so thatthere is always a wee bit left when she comesto give me my next lot. Soaking hay for 12hrsgets rid of most of the calories, but it alsoleaches out the protein, vits and mins…so I need a balancer, (shhhh don’t tell anyonebut I swear by Ultimate Balancer…..it hasloads of stuff in it, but is so low in caloriesand gives me little or no starch so I can justkeep eating my fibre)

Forage and occupational therapy

Dr Teresa Hollands R.Nutr

T H E M AT U R E H O R S E

SPRING 2011 ISSUE EQUINE MATTERS 12

Don’t know if you had time to see the BBCprogramme on the ‘Young Ones’? It followedhumans in their 70’s and 80’s and showedhow by taking a positive attitude, movingmore, being independent, having to think foroneself and not be mollycoddled, improvedtheir cognitive and fitness levels within just one week!!

So to keep me sprightly, please treat me likea younger horse, whilst keeping an eagle eyefor me getting too fat or stiff...

It’s not complicated being old really, (middleaged)…just keep us warm and give us shelter,loads of low calorie forage and a decentfeed balancer. If we are unable to eat foragethen get us onto a hay replacer and an oldhorse diet. In light of that new survey, thenplease get my teeth and feet done regularlyby a professional; also get the vet to do me an MOT every year, even if there appears to be nothing wrong; prevention is better than cure.

Let us keep moving around andplease don’t make us fat; itshortens our life. And me? WellI’ve loads of rosettes yet to winand a filly or two to meet!

When are we old?The researcher who found that we need more and different nutrients back in the 80s,(Professor Sarah Ralston) has done morework; she now knows that because we arelooked after so much better that the differentnutrient requirements don’t exist. Really weonly need a special feed like 16+ when weshow signs of aging such as weight loss,problems chewing and stiffness.

Guess the most significant effect on us interms of what makes us old, is when the old teeth wear out. Then we can’t eat hayanymore and it doesn’t really matter whatfancy feed they give us; it is VITAL that theysort out a fibre replacer first.

I’ve a stablemate, who’s 30, and I have tokeep an eye out for the old chap, he’s startedquidding and his muscle tone is going, wellhis owner doesn’t ride him anymore and youknow what they say,; ‘if you don’t use it,you’ll lose it’. I’m hoping my ‘Mistress’ getsher Mum to call the D&H helpline to chatabout hay replacers.

The best one I know about is...l High Fibre Nuts (damped just to make

them soft)l Kwick Beet or unmolassed sugar

beet shredsl Alfalfa chaff or Just Grass (no straw chaffs,

can’t chew them well enough)l Start with a small handful of each in a

feed bucket and gradually increase over14 days

l Probably will need 600g/100kg bodyweight of each product, so you are eating 1.8% of your bodyweight as forage

l Remind your mum that this is the equivalentof half a bale of hay a day, so there willbe loads, but we need that amount!

l If you’ve got diastemas (and the latestwork from Liverpool University found that43% of us do) then you can’t eat short orlong fibre - it just gets stuck!!

WHEN WE ARE OLD?

Work carried out by a team at LiverpoolUniversity Vet School, Leahurst (supportedby The Horses Trust) was presented by JoIreland at BEVA. She researched a group of old horses to characterise what beingold in horse terms means.....humph

Did you know?l 96% of old horses had dental

abnormalities (average age = 20yrs but varied between 15-40yrs)

l 26% of us are overweight, with only4.5% being underweight

l Scarily 49% of us were lame in trot...and our owners often didn’t realise

l 18% of us had curly coats (hirustism)

l 80% of us had hoof abnormalities

The Mature Horse...

S K I N D I S E A S E

13 EQUINE MATTERS

Binscarth Farms

There are many agents which cause allergic skin disease in animals but theycould be broadly categorised into insect

bite reactions, food allergies, contact allergiesand allergies to environmental agents such aspollens, dust mites or mould spores.

In most individuals an insect will bite an animal to suck its blood, at the same time itwill leave a small amount of its saliva which is normally absorbed by the body in a shortperiod of time. However some individual animals have an immune reaction which causes an excessive reaction to the insect saliva, causing the skin to become very itchy.The animal then rubs and scratches itself making large sore patches. A good exampleof this in horses is Sweet Itch in which poniesthat are allergic to the bites of midges orBlack Flies (Culicoides), rub themselves rawon the tail and mane and under the belly.

This has a hereditary component and is seenparticularly in certain breeds such as Shires,Icelandic and Welsh ponies. The midges are particularly prevalent near areas of free standing water and when there are low winds in the early morning or late evening insummer and autumn. Management thereforeinvolves preventing the midge from biting so having horses stabled between 4pm and 8am and covering the animal in ashroud/hood can help (e.g. The BoetBlanket). A fine mesh screen over stable windows, having fans in the stable to createa breeze, and using fly repellents can help.Anti-inflammatory medication includes glucocorticoids; oral preparations can precipitate laminitis, but topical preparationscan be beneficial. Desensitisation using anallergy vaccine has been investigated and the results are still being analysed so no commercial preparation is available yet.

Allergic Skin Disease in Horses...An allergic reaction is an inappropriate reaction of an individualanimal's immune system to a harmless agent that it is exposed towhich, the majority of animals would not react to.

Veterinary Surgeon Richard Morris

XLVets Practice Fenwold VeterinaryPractice,Lincolnshire

Richard Morris BSc, BVetMed, CertVD, MRCVS

Horse with Sweet Itch

S K I N D I S E A S E

SPRING 2011 ISSUE EQUINE MATTERS 14

ALLERGIC TO MEDICATION

Some horses can be allergic to certaindrugs; when given medications whichwould not affect normal individuals, theyreact in an adverse way potentially causing some serious reactions. The following case developed large areas of irregular bumps in the skin followingthe administration of a routine wormer,the reaction went down after a while but the owner was careful to avoid anysimilar wormers again.

Another allergic reaction to an insect bite isHives or Uritcaria in which a sting from a beeor wasp causes large swellings to appear allover the body. In the case opposite the headhad swollen up and the nose band of thehead collar had left an impression where ithad become tight and prevented furtherswelling. This resolved after being given intravenous medication but caused the horseconsiderable distress at the time.

Allergies to environmental agents can beeither from direct contact or by a systemicreaction once the allergen has been inhaled.Some animals develop an allergic reaction to something their skin comes into contact with such as certain types of bedding.

The horse below came out in large skin reactions when its bedding was changedfrom wheat to barley straw. The lumps wentdown with treatment and changing the bedding, but relapsed once exposed to Barley Straw again.

The predisposition to allergic symptoms following repeated exposure to inhalant allergens is called Atopic Dermatitis andArabians and Thoroughbreds appear to bepredisposed to the condition. Common allergens include: pollens, moulds, and DustMites, and the reaction causes intense itching.The horse bites at itself and rubs itself onfences and stable walls causing self inflicted damage with hair loss and ulceratedskin lesions. The disease can be investigatedby allergy testing where extracts of commonenvironmental agents are injected into the skinand the reaction measured. The followinghorse was identified as being allergic to Dust Mites and once kept out at grass and the exposure to stable dust reduced its condition improved.

Reducing the exposure of an animal to theallergens by regular shampooing with a mild soothing shampoo can also be beneficialand corticosteroids in the short term to suppress the sensitivity of the skin to the allergenic agents is helpful, but long term usecan be harmful with side effects includingLaminitis and liver damage.

ENVIRONMENTAL AGENTS

CONCLUSION

So there are a wide variety of allergic reactions horses can develop producing a range of clinical signs. Painstaking investigation to get to the bottom of the cause can be very helpful in managing the problems and allowing the horse to continue a comfortable life.

Horse with Uritcaria (Hives)

Reaction to a bedding change from wheat to barley straw

Horse allergic to dust mites

Allergy testing

A I R WAY A N AT O M Y

15 EQUINE MATTERS

Veterinary Surgeon Mark Tabachnick

XLVets Practice Wright & MortenMacclesfield

The horse's airway is divided into the upper respiratorytract; which starts at the nostrils and ends at the larynx at the back of the throat, and the lower respiratory tract;the trachea and the lungs.

Airway Anatomy

The nostrilsHorses’ nostrils are naturally very large, butare also very flexible. They are supported bya cartilage called the alar cartlilage, andhave a well developed muscle attachment.This means at strenuous exercise, they arecapable of massive dilation to allow in moreair. Within the nostril there is a blind endingpouch called the false nostril, which appearsto have no anatomical function.

The nasal cavityThe nasal cavities stretch from the nostrils tothe throat. They are divided into a series ofnarrow passageways by thin strips of bonescalled turbinates. In between the turbinatesare a series of passageways where the airruns freely. The turbinates are lined by a layerof tissue with a good blood supply called

mucosa. This functions to warm and moistenthe air before it reaches the lungs.

The nasal cavities overlie the tooth roots of the horse's molar teeth, and are closely connected to the sinuses. The sinuses are aseries of air filled chambers within the horse'sskull. Their exact function is unknown. Theymay have evolved to allow the bony skull tobe relatively light. The sinuses communicatewith the nasal cavity via a small opening.

At the back of the nasal passages are a number of mushroom shaped projectionscalled ethmoturbinates. These are importantfor the horse's sense of smell.

Mark Tabachnick BVM&S, BSc, CertEP, MRCVS

A I R WAY A N AT O M Y

SPRING 2011 ISSUE EQUINE MATTERS 16

The pharynxThe nasal passages enter the throat into an area called the nasopharynx. The oralcavity enters at the back of the mouth into the oropharynx. These regions then form thepharynx. Here nerve activity controls themovement of food down into the oesophagus,and the movement of air towards the lungs.

At the back of the nasopharynx are small slits, which make the openings of the gutturalpouches. Guttural pouches are the enlargements of a tube that starts at thehorse's inner ear. They are large cavities, and many of the most important blood vesselsand nerves of the head run along their walls.Again, their function remains unknown.

The larynxThe larynx lies at the back of the pharynx and at the entrance of the windpipe (the trachea). It is a complexarrangement of cartilages controlled by ligaments and nerves. It protects the airwaywhen horses swallow, so stopping food entering the windpipe. It controls the amountof airflow entering the lungs. It is alsoinvolved in producing vocal noises.

The larynx does all this by using a pair of cartilages, called the arytenoids. These cartilages can move towards and away fromeach other to increase or decrease the size of the opening into the trachea. When ahorse is eating, the arytenoids will close theopening. When a horse is exercising, the arytenoids will be raised out of the wayallowing a resistance free passage for air totravel into the lungs. A cartilage flap calledthe epiglottis holds the horse's soft palate clear of the breathing hole.

The tracheaBifurcation of the trachea into the two bronchi.

The windpipe or trachea is a rigid circulartube that transports air from the larynx to thelungs. It is composed of rings of cartilagejoined together by sheets of connective tissue.This means that it is very difficult for the trachea to collapse, whatever position thehorse's neck is in. The trachea contains cellswhich produce mucus, a substance which will trap the inhaled dust and dirt, and specialised cells called cilia which have long

tails. These constantly beat the mucus up intothe pharynx where it is swallowed.

The lungsAs the trachea enters the lungs, it splits intotwo bronchi. One bronchi enters each lung.The bronchi constantly divide into smallertubes called bronchioles. These bronchi furthersubdivide rather like the branches of a tree.The smaller airways are again lined withmucus producing cells and cilia to removetrapped dust. The bronchioles can expandand contract slightly to increase or decreasethe size of the airway.

At the end of the bronchioles are the alveoli.These are tiny sacs with very thin walls, with a rich blood supply. As the air reaches thesesacs, the oxygen is dragged into the redblood cells in the capillary walls and transported around the body. At the sametime, the red blood cells release their load ofcarbon dioxide which is a waste productpicked up from the body tissues. The carbondioxide is released into the alveoli.

The pleural cavityThe lungs sit within the horse's chest cavity,lined by a thin membrane called the pleura.The pleura forms a closed sac around thelungs. This means the lung space is an areaof negative pressure which allows the lungs to easily expand and contract.

The lungs are bordered by the ribs aroundtheir outside. The diaphragm is a thick muscular sheet along the bottom of the lungs which separates them from the horse's abdomen.

BreathingAs a horse breathes, the chest wall and ribsmove upwards and outwards, increasing thewidth of the chest. The diaphragm contracts,moving downwards, increasing the depth ofthe chest. This allows the lungs to expand asthey fill with air, and they can now fill thelarger chest cavity. Air is drawn into the lungs,and follows the passageway to the alveoli.Gas exchange occurs - oxygen is exchangedfor carbon dioxide.

As the horse breathes out, the chest musclesand the diaphragm both relax. The chest cavity now gets much smaller. The elastic lungtissue now recoils. These actions drive air outof the lungs and back into the atmosphere.

M A R K TA B AC H N I C K

Fact... At maximal exertion a horse can breathe in as much as 4,500 litres of air in one minute!

COMMON RESPIRATORYCONDITIONS

UPPER RESPIRATORY TRACT

Idiopathic Laryngeal Hemiplegia (ILH)This condition is often known as roaring or whistling. In ILH, horses lose the nervesupply to the left arytenoid cartilage. When horses exercise, they can no longermove this cartilage back and forward. It sits within the airway causing the horse to make a whistling type of noise as theybreathe in at the canter. This obstruction will decrease the amount of air a horsetakes in at exercise, and so may decrease their athletic performance.

Dorsal Displacement of the Soft Palate(DDSP)DDSP is a condition that occurs at intenseexercise, and is commonest in young race-horses and eventers. In this conditionthe soft palate, which is usually held inplace by the epiglottis, flips out of positionand billows loosely at the back of the pharynx, often blocking the airway. Thecondition is usually transient. Riders reportthat the horse was going well at the gallopuntil suddenly choking or gurgling andpulling up. The soft palate will often return to its usual position very quickly.

LOWER RESPIRATORY TRACT

Recurrent Airway Obstruction (RAO)This condition used to be called ChronicObstructive Pulmonary Disease (COPD). It is often called heaves. Very commonly,this is an allergy to dust in the environment and results from horses being kept in poorly ventilated stables. Horses sufferingfrom RAO have fast shallow breathing, can cough and be quite distressed. It canbe treated by using medications whichopen the airways making breathing easier. Good quality air flow is the key tomanagement. Always ensure the horse iskept in a well ventilated stable.

Summer Pasture Associated ObstructivePulmonary Disease (SPAOPD)This condition can be similar to RAO, butoccurs to horses out at grass often duringthe summer. Horses show very similar signsto those with RAO, but are allergic to pollens in the atmosphere rather than dust.It can be managed by stabling the horseaway from the inciting pollens.

If you have not been able to ride your pony so much over winter remember

it will take time to get him fit again. Time spent walking and trotting now

will help him stay healthy and sound through the rest of the year.

Your pony will start to moult and shed his winter coat before he gets all

sleek and shiny for the summer. He will need regular grooming to help

get rid of that hairy hippo look.

While he still has his winter coat he will get very sweaty when ridden as

the days get warmer. Have him clipped if you are going to be doing a

lot of galloping or jumping. Watch out for sweaty hairy ponies getting

cold, they take a long time to dry.

Before you start going to lots of shows check your pony's flu jabs are

up to date

Worms thrive in warm moist conditions so make sure you

worm your pony in the spring, write down when you do

it on a calendar. Ask your vet what to use.

Spring means mud, if your pony lives out check his feet daily

for thrush, where the bit at the side of the frog goes wet, black

and stinky. Watch out too for mud fever and rain scald on the

legs and back, where the legs become swollen sore and scabby,

be especially careful if your pony has white socks.

If your pony goes out into a new field for the spring check it is safe,

check the fences and hedges for gaps, look out for any poisonous

plants coming through. Check the water supply or trough is clean.

Spring is when the grass starts to grow, to stop your pony getting

laminitis make sure he can’t spend all day munching. Watch out

for him getting a hard cresty neck.

Too much lush spring grass can also give your pony tummy ache so be

careful when letting him out onto grass for the first time - only leave him

out for a couple of hours. Remember to make all changes to what he

eats gradually.

Finally this is time for a good spring clean! Check all your tack is safe

and in good repair, clean your grooming kit and tidy out all those feed

bins to get rid of any old mouldy feed that may be lurking around.

CONGRATULATIONS TO...

COMPETITION 5 WINNER

ScottMitchell Associates Winner:

Georgina Clarkson pictured

above wearing her pink prize!!

Welcome...TO THE SPRING 2011XLVETS PONY PAGES

...To help you and your pony get in shape for summer

By Jane King Westmorland Veterinary Group

Did you know - when firstborn, a foal cannot

eat grass because theirlegs are too long

and the foal cannot reach the grass!

FOR SPRING!

A winner will be chosen from all the correct entries received before the closing date, Thursday 21st April 2011. The winner will be revealed in the next issue of Equine Matters. The editor’s decision is final, no correspondence will be entered into.

THE NUMBER OF DIFFERENCES:

Name

Address

Daytime Telephone Number

Email

XLVets Practice Name

Postcode

Send your completed entry to: Equine Matters Competition No.6 XLVets, Carlisle House, Townhead Road, Dalston, Carlisle, CA5 7JF

I do not wish to receive further information from XLVets

I would like to receive further information from XLVets by e-mail

WelcomeXLVets Competition

How many differences can you spot between the two pictures below.

Circle the differences as you find them, then write how many you can

find on the competition entry form below and send it back to us for

YOUR CHANCE TO WIN.

ENTERTODAYGOOD LUCK...

CONGRATULATIONS TO...

COMPETITION 5 WINNER

ScottMitchell Associates Winner:

Georgina Clarkson pictured

above wearing her pink prize!!

WIN an Equestrian Bag, containing six items including a small body brush,dandy brush, flick brush, face brush, hoof pick and sweat scraper.

Answer to Autumn 2010 competition: Rosette

For further Equine Information, please contact your local XLVets Practice.

www.xlvets.co.uk